A device, including a low-ohmic circuit path; a normal operation circuit path coupled in parallel with the low-ohmic circuit path; and a circuit element configured to select between the low-ohmic circuit path and the normal operation circuit path.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A device, comprising: a low-ohmic circuit path coupled at one end directly to an input of the device and at the other end directly to an output of the device; a normal operation circuit path coupled in parallel with the low-ohmic circuit path; and a circuit element configured to select between the low-ohmic circuit path and the normal operation circuit path, wherein when the device is operating in a normal mode, is configured to select the normal operation circuit path, and when the device is not powered or is in a failure mode, is configured to select the low-ohmic circuit path.
2. The device of claim 1 , wherein the circuit element is configured to select between the low-ohmic circuit path and the normal operation circuit path based on a supply voltage.
3. The device of claim 2 , wherein: the circuit element comprises an under-voltage lockout (UVLO) circuit configured to detect whether the supply voltage is above a predetermined threshold voltage, if the supply voltage is not above the predetermined threshold voltage, the UVLO circuit selects the low-ohmic circuit path, and if the supply voltage is above the predetermined threshold voltage, the UVLO circuit selects the normal operation circuit path.
4. The device of claim 3 , wherein the low-ohmic circuit path comprises a switch and a resistor coupled in series, and the UVLO circuit selects between the low-ohmic circuit path and the normal operation circuit path by controlling the switch.
5. The device of claim 2 , further comprising: a checker circuit configured to check a status of the device for an error or failure, and configured to select the low-ohmic circuit path even if the device is receiving the supply voltage.
6. The device of claim 1 , wherein the low-ohmic circuit path comprises a bi-directional normally-on switch between an input and an output of the device.
7. The device of claim 6 , wherein the switch is comprised of two anti-serially coupled normally-on transistors.
8. The device of claim 1 , wherein the circuit element is further configured to detect an operation failure of the device.
9. The device of claim 1 , wherein the circuit element is further configured to switch from transparent pin mode to normal operating mode when a defined status of input(s) of the device has been detected.
10. A daisy-chain circuit, comprising: at least one slave device comprising: a low-ohmic circuit path having a first end coupled directly to an input of the at least one slave device and a second end coupled directly to an output of the at least one slave device; a normal operation circuit path coupled in parallel with the low-ohmic circuit path; and a circuit element configured to select between the low-ohmic circuit path and the normal operation circuit path, wherein when the device is operating in a normal mode, is configured to select the normal operation circuit path, and when the at least one slave device is not powered or is in a failure mode, is configured to select the low-ohmic circuit path; and a master device coupled to the at least one slave device, wherein the at least one slave device and the master device are coupled in a daisy-chain configuration, and the daisy-chain configuration is operable when the at least slave device is not powered or is in the failure mode.
11. The daisy-chain circuit of claim 10 , wherein the master device is configured to detect a length of the daisy-chain circuit by determining a length of time for a unique data pattern to be transmitted from and return to the master device, wherein the length of time corresponds to the length of the daisy-chain circuit.
12. The daisy-chain circuit of claim 10 , further comprising: a plurality of slave devices of claim 1 coupled in the daisy-chain configuration.
13. The daisy-chain circuit of claim 12 , wherein each of the plurality of slave devices is configured to transmit a unique data pattern to the master device, and wherein the master device is configured to detect, based on the respective unique data patterns, which of the plurality of slave devices has its low-ohmic circuit path selected.
14. The daisy-chain circuit 12 , wherein an output current of the master device or of one of the plurality of slave devices is used to determine if another slave device is in transparent pin mode.
15. The daisy-chain circuit of claim 12 , wherein an input voltage of the master device or of one of the plurality of slave devices is used to determine if another slave device is in transparent pin mode.
16. The daisy-chain circuit of claim 12 , wherein each of the slave devices comprises a pull-down resistor configured to force an input pin of the respective slave device to ground.
17. The daisy-chain circuit of claim 16 , wherein if a specific one of the plurality of slave devices has its normal operation circuit path selected, the upstream neighboring slave device is configured to detect only the pull-down resistor of the specific slave device.
18. The daisy-chain circuit of claim 16 , wherein if a specific one of the plurality of slave devices has its low-ohmic circuit path selected, the upstream neighboring slave device is configured to detect the pull-down resistor of both the specific slave device and the downstream neighboring slave device.
19. The device of claim 1 , wherein the device is a master device or a slave device.
20. A method of operating a device having a low-ohmic circuit path and a normal operation circuit path coupled in parallel and at one end directly to an input of the device and at the other end directly to an output of the device, the method comprising: selecting the low-ohmic circuit path if the device is not powered or is in a failure mode; selecting the normal operation circuit path when the device is operating in a normal mode; and switching from the low ohmic circuit path to the normal operation circuit path after some delay has elapsed, defined information has been received, or a defined status of communication pins of the device has been detected.
21. The method of claim 20 , wherein the device is a master device or a slave device.
22. A method of operating a daisy-chain circuit including a master device and a plurality of slave devices, comprising: detecting if any of the plurality of slave devices has a low-ohmic circuit path selected, wherein each of the plurality of slave devices has the low-ohmic circuit path having a first end coupled directly to an input of the respective slave device and a second end coupled directly to an output of the respective slave device, a normal operation circuit path coupled in parallel with the low-ohmic circuit path, and a circuit element configured to select between the low-ohmic circuit path and the normal operation circuit path, wherein when the device is operating in a normal mode, is configured to select the normal operation circuit path, and when the device is not powered or is in a failure mode, is configured to select the low-ohmic circuit path; and changing data transmitted by the master device according to a number of the plurality of slave devices having its normal operation circuit path selected.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
April 15, 2016
May 12, 2020
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